No one was injured in the blast at Wattle Bridge close to Newtownbutler on Monday morning.
Bomb disposal officers - Ammunition Technical Officers (ATO) - had been in the area at the weekend responding to reports that a device had been left there.
That item was ultimately declared a hoax but another device exploded close-by at around 10.35am on Monday when a bomb disposal team was attending to review the scene. Police were also in attendance, patrolling a security cordon.
Police Service of Northern Ireland (PSNI) Deputy Chief Constable Stephen Martin said: "While this investigation is at a very early stage I am of the firm belief this was a deliberate attempt
to lure police and ATO colleagues into the area to murder them.
"Although this device was intended to kill police and Army personnel the fact that it was placed on a main road the result could well have been devastating for anyone in the immediate vicinity."
The finger of suspicion will again point to dissident republicans opposed to the peace process.
Mr Martin added: "This attack was indiscriminate and reckless and, whilst there is no doubt in my mind that police responding to this call were the target, the reality is that anyone could have been caught up in the explosion.
"We are extremely fortunate that the actions of officers who were first on scene meant that there was not serious injury or death. I wish to acknowledge and commend the bravery and commitment of those officers and Army personnel at the scene of this attack.
"I would like to again thank the community for their patience and cooperation throughout the security operation as we seek to ensure their safety. The area around the scene will remain closed for some time while our officers conduct their investigations and ensure the area is safe.
"I ask that anyone who may be able to help our investigation and identify the perpetrators of this sinister and potentially murderous attack to please come forward."
Dissident extremists continue to target members of the security forces in Northern Ireland.
Last month, an explosive device detonated on the Tullygally Road in Craigavon, Co Armagh, as police attended a call-out from a member of the public.
Commanders said it was a set up to lure officers into the area ahead of the murder bid.
In June, a serving police officer had a lucky escape when he found an under-car booby trap bomb attached to the underside of his vehicle in a golf club car park in east Belfast.
Fermanagh and South Tyrone MP Michelle Gildernew condemned those responsible for Monday morning's incident.
"This morning's bomb attack in Wattle Bridge was totally wrong," said the Sinn Fein representative.
"Thankfully no one was injured in this incident but we could have been dealing with a situation where people were seriously injured or worse.
"Those responsible for this incident have nothing to offer society and need to end these actions immediately.
"Anyone with information on this should bring it forward to the PSNI."
PSNI Chief Constable Simon Byrne tweeted: "The bomb attack in Fermanagh this morning is a sinister development. A clear and deliberate attempt to murder @PoliceServiceNI officers. I strongly condemn these actions and express my sincere thanks to both the Officers and Army personnel for their work in securing the area."
Ireland's Taoiseach Leo Varadkar tweeted: "I strongly condemn the cowardly actions of those responsible for the bomb attack in Co Fermanagh this morning, which could have had
devastating consequences. There is never any justification to use violence to achieve political aims.
"The people of Ireland, North and South, had their say on this issue when they voted overwhelmingly and emphatically for the Good Friday Agreement. It is a considerable relief that no PSNI officers were seriously injured or killed when this bomb went off.
"We should be in no doubt that this device was intended to inflict maximum harm. I encourage anyone who has information on this incident to provide it to the PSNI, so that those responsible can be brought to justice and future attacks prevented."